Amino-Functionalized Fe3O4@SiO2 Core-Shell Magnetic Nanoparticles for Dye Adsorption

Abstract

Fe3O4@SiO2 core-shell nanoparticles (NPs) were synthesized with the co-precipitation method and functionalized with NH2 amino-groups. The nanoparticles were characterized by X-ray, FT-IR spectroscopy, transmission electron microscopy, selected area electron diffraction, and vibrating sample magnetometry. The magnetic core of all the nanoparticles was shown to be nanocrystalline with the crystal parameters corresponding only to the Fe3O4 phase covered with a homogeneous amorphous silica (SiO2) shell of about 6 nm in thickness. The FT-IR spectra confirmed the appearance of chemical bonds at amino functionalization. The magnetic measurements revealed unusually high saturation magnetization of the initial Fe3O4 nanoparticles, which was presumably associated with the deviations in the Fe ion distribution between the tetrahedral and octahedral positions in the nanocrystals as compared to the bulk stoichiometric magnetite. The fluorescent spectrum of eosin Y-doped NPs dispersed in water solution was obtained and a red shift and line broadening (in comparison with the dye molecules being free in water) were revealed and explained. Most attention was paid to the adsorption properties of the nanoparticles with respect to three dyes: methylene blue, Congo red, and eosin Y. The kinetic data showed that the adsorption processes were associated with the pseudo-second order mechanism for all three dyes. The equilibrium data were more compatible with the Langmuir isotherm and the maximum adsorption capacity was reached for Congo red.

Construction of Fe3O4/xSiO2/ySiO2 Nanoparticles for Pesticide Removal from Water: Improved Dispersion Stability and Adsorption Capacity

“…400), ( 422), (511), and (440), indicating that they had face-centered cubic structures. 69 The broadband at about 22°w as due to the amorphous peak generated by the amorphous SiO 2 . 70,71 These results indicate that core−shell nanoparticles were successfully synthesized without destroying the crystal structure of Fe 3 O 4 cores during SiO 2 coating and surface functionalization.…”

Microgels as Smart Polymer Colloids for Sensing and Environmental Remediation

“…In the existing literature, composite microgels exhibited very good adsorption behavior for various pollutants such as heavy metal ions, dyes, pharmaceuticals, etc. Since some composite microgels can be easily synthesized and redeveloped, they have been considered as a promising entrant for wastewater treatment. − Adsorption capacity or elimination efficiency of the composite microgels can be tuned by the change of different parameters such as temperature and pH of the solution. On the other hand, efficiency also depends on the use of different constituent materials in composite microgels such as nonpolymeric materials and metals.…”

One-Step Fabrication of Amino-Functionalized Fe3O4@SiO2 Core-Shell Magnetic Nanoparticles as a Potential Novel Platform for Removal of Cadmium (II) from Aqueous Solution

“…From the previous studies [39], it was reported that the 3-aminopropyltrimethoxysilane (APTS) functionalized Fe 3 O 4 @SiO 2 nanoparticles exhibit a similar spinel structure with the face centered cubic (FCC). Various researchers showed that the (3-aminopropyl)-triethoxysilane (APTES) functionalized Fe 3 O 4 @SiO 2 nanoparticles exhibit a similar spinel ferrite crystal structure [40,41]. The synthesized amino-functionalized Fe 3 O 4 @SiO 2 nanoparticles show spinel ferrite patterns [42].…”